1. Field of the Invention
The present invention relates to a process for transmitting status messages to user terminals of a satellite data transmission system which is embodied for the data transmission of user data blocks from satellites to the user terminals. Such satellite data transmission systems can in principle transmit different types of user data, such as communication data or multi-media data, as well as navigation data, as is known, e.g., from U.S. Pat. No. 6,205,377. The present invention is fundamentally applicable to all types of such satellite data transmission systems.
2. Discussion of Background Information
It can be necessary in such satellite data transmission systems, in addition to the usual user data, to also transmit additional status messages such as, e.g., identification data of system components, version data of certain software, also traffic information for ground, water or air transportation. Modifications of the status information can also occur, such as, e.g., modifications of software versions, of flight routes in air traffic information, or congestion developing in ground traffic information. In the case of transmitting navigation data, integrity information can be provided as status messages, which integrity information can provide information on the integrity of a satellite navigation system. Here too time modifications of the integrity information can occur. Taking integrity information into consideration within the scope of satellite navigation systems is likewise fundamentally known from U.S. Pat. No. 6,205,377 and from J. Benedicto et al. GALILEO: Satellite System Design and Technology Developments, European Space Agency, November 2000, which can be downloaded, e.g., at http://ravel.esrin.esa.it/docs/galileo_world_paper_Dec—2000.pdf.
However, such status messages can hinder either the transmission of the user data to the user terminals or the evaluation of the user data or the user data signals in the user terminals if the transmission of the status messages takes place at a high data rate. However, if the transmission of the status messages occurs at a low data rate, an updating of the status messages in the user terminals can occur only slowly or inadequately.